Hi All,
I need help to solve the problem.
I just completed the aleph J and noted a very loud cracking sound through the loudspeaker on switch off of the power supply.
It is very quiet on switch on and no hum at all.
The dc offset at output is less than 0.2 V but swing to about 1 to2 V on powering down.
I am using a CLC type of line filtering with about 200000UF caps. The L is wound on a EI transformer , diy type.
I also use about 11 uF of motor start non polar caps at the last stop.
Could this be the problem ?

Hi kp9etc,
Sounds very much like arcing inside the power switch. Suggest you put snubbers/switch click suppressors across each section of the switch, consisting 0.1µF "Y" type capacitor in series with 100-120R resistor, or buy them ready made from RS or farnell.

Hi kp9etc,
Sounds very much like arcing inside the power switch. Suggest you put snubbers/switch click suppressors across each section of the switch, consisting 0.1µF "Y" type capacitor in series with 100-120R resistor, or buy them ready made from RS or farnell.

John

Will a 1/2 w resistor be ok ?
Can I use x2 rated ? Is the value of 0.1uF critical ? Smaller and larger value ?

These are some pictures of the aleph j that I build.
The transformer is in another box.
The pre is J310 and Lightspeed clone as the attenuator.
hope i can find some pointers in troubleshooting this problem.